Fig. 3. Experiment 2, stimulus and value space neural representations.

(a) Trial timeline. (b) Illustration of repetition suppression effect. (c) Hexagonal symmetry (in black) of the receptive field of an ideal grid-cell (in grey) and a trajectory (in red) between two locations. (d) Illustration of the angle of the trajectory (in red) in value space from one option to the next. The angle is relative to a fixed orientation (dotted line). (e) Repetition suppression effect for option identity, cluster-corrected within frontal cortex. Test based on sessions 3 to 5. (f) Quadrature test for a hexagonal symmetry: average F values, P < 0.001 uncorrected (group level F-statistic cluster-correction is not possible²⁶). (g) Nonparametric test of the average F values for periodicities from four- to eight-fold; randomized null distribution on the right; a Bonferroni correction with factor 5 is applied; Results did not change with periodicity-specific null distributions (Extended Data Fig.4g). Data in panels g-h-i are from the MFC ROI defined independently in experiment 1. (h) Average phase difference between grid orientation estimates from two interleaved trial subsets from each session. Right: a priori null distribution. (i) Illustration of Kolmogorov-Smirnov test: empirical and a priori cumulative distribution functions (CDF) of phase differences across sessions. * P < 0.05, ** P < 0.01. In all panels (except e) n=4 monkeys x n=5 sessions.